Antarctica was once home to rain forests

Drilling of the seabed off Antarctica has revealed that rain forest grew on the frozen continent 52 million years ago, scientists said Thursday, warning it could be ice-free again within decades.

The study of sediment cores drilled from the ocean floor off Antarctica's east coast revealed fossil pollens that had come from a "near-tropical" forest covering the continent in the Eocene period, 34-56 million years ago.

Kevin Welsh, an Australian scientist who traveled on the 2010 expedition, said analysis of temperature-sensitive molecules in the cores had showed it was "very warm" 52 million years ago, measuring about 68 degrees F.

"There were forests existing on the land, there wouldn't have been any ice, it would have been very warm," Welsh told AFP of the study, published in the journal Nature.

"It's quite surprising, because obviously our image of Antarctica is that it's very cold and full of ice."

Welsh said higher levels of carbon dioxide in the atmosphere were thought to be the major driver of the heat and ice-free conditions on Antarctica, with CO2 estimates of anywhere between 990 to "a couple of thousand" parts per million.

CO2 is presently estimated at about 395ppm, and Welsh said the most extreme predictions by the Intergovernmental Panel on Climate Change would see ice again receding on Antarctica "by the end of the century."

"It's difficult to say, because that's really controlled by people's and governments' actions," said Welsh, a paleoclimatologist from the University of Queensland. "It really depends on how emissions go in the future."